Genetic products maker Affymetrix Inc (AFFX) has announced disappointing preliminary sales for second-quarter fiscal 2011. The California-based company expects to post revenues in the band of $64-65 million for the quarter, which is below the current Street view of roughly $74 million. Affymetrix’s shares tanked $1.55 (or 19.4%) to $6.45 in after-hours trading on July [...] (AFFX) Affymetrix’s Second Quarter Preliminary Sales Miss